The object of the present invention is to reduce the load and specification requirements on the network and the video server. The buffer usage rate is counted and supplied to the tape driving controller 7. In the reproduction mode, the tape driving controller 7 decreases the running speed of a video tape when the buffer usage rate is larger than the proper value. And when the buffer usage rate is smaller than the proper value, the tape driving controller 7 increases the running speed of the video tape. Moreover, in the recording mode, the tape driving controller 7 stops the tape motion temporarily if the transmission speed of the network is slow and the buffer usage rate declines lower than the proper value. And if the buffer usage rate increases over the proper value, the tape driving controller 7 resumes the tape driving to record signals. Thus, the reproduction speed or the recording speed by the tape driving device 3 can be coincided with the transmission speed of the network.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A video tape recording/reproducing device for recording video data on a video tape and reproducing the video data recorded on the video tape, comprising: driving means for driving the video tape at a predetermined running speed; a rotatable drum having a plurality of magnetic heads for executing reproduction and recording of the video data from/to the video tape; a buffer memory for temporarily holding the video data to be reproduced by said heads or the video data to be recorded, counting a rate of change of a current data quantity stored in the buffer memory to an entire memory capacity, and supplying the rate of change to a driving control means; an interface for asynchronously transmitting the video data between an external equipment and said buffer memory; and driving control means for controlling the running speed of said video tape by said driving means in accordance with the current data quantity stored in said buffer memory and the rate of change of the current data quantity stored in the buffer memory to the entire memory capacity, both supplied from the buffer memory, wherein a range of the running speed is a function of a fixed number of the plurality of heads; whereby the video data is recorded on the video tape in the form of multiple tracks; whereby the magnetic heads are arranged in pairs, the heads in each pair are spaced apart by about one track width, and the heads in each pair have about the same azimuth angle; whereby said device is operable to perform a variable speed reproduction in which all of the video data recorded on the video tape is reproduced by changing the tape running speed without changing the drum rotation speed; and whereby the video tape is housed within a cassette that includes a non-contact type buffer memory for storing a list of contents of the video tape, the non-contact type buffer memory including a drive circuit for controlling said memory, being read when data is reproduced from the tape and being written when data is recorded to the tape.
2. A video tape recording/reproducing device as defined in claim 1 , wherein: said driving control means controls the running speed of said video tape; and said driving control means is controlled in such a manner that, when the data quantity stored in said buffer memory is larger than a predetermined value, the video tape running speed is lowered, while when the data quantity stored in said buffer memory is smaller than the predetermined value, the tape running speed is increased.
3. A video tape recording/reproducing device as defined in claim 1 , wherein: said driving control means controls said driving means in such a manner that, when the data quantity stored in said buffer memory becomes lower than a predetermined value, the running of said video tape is suspended temporarily, while when the data quantity stored in said buffer memory becomes higher than the predetermined value, the motion of said video tape is started again in order to restart the recording on the video tape.
4. A video tape recording/reproducing device as defined in claim 3 , wherein: said driving control means controls said driving means so that the video tape is returned by a fixed distance in the opposite direction to be ready for restarting the next recording after the running of said video tape is temporarily brought to a stop.
5. A video tape recording/reproducing device as defined in claim 1 , comprising: memory write/read means for reading out the recorded contents of the memory means attached to said video tape in order to memorize the information to control the contents recorded on said video tape and for writing these.
6. A video tape reproducing device for reproducing the video data recorded on a video tape, comprising: driving means for driving said video tape at a predetermined running speed; a rotatable drum having a plurality of magnetic heads for executing reproduction of the video data from the video tape; buffer memory for temporarily holding the video data to be reproduced by said heads, counting a rate of change of a current data quantity stored in the buffer memory to an entire memory capacity, and supplying the rate of change to a driving control means; an interface for asynchronously transmitting the video data between an external equipment and said buffer memory; and driving control means for controlling the running speed of said video tape by said driving means corresponding to the current data quantity stored in said buffer memory and the rate of change of the current data quantity stored in the buffer memory to the entire memory capacity, both supplied from the buffer memory, wherein a range of the running speed is a function of a fixed number of the plurality of heads; whereby the video data is recorded on the video tape in the form of multiple tracks; whereby the magnetic heads are arranged in pairs, the heads in each pair are spaced apart by about one track width, and the heads in each pair have about the same azimuth angle; whereby said device is operable to perform a variable speed reproduction in which all of the video data recorded on the video tape is reproduced by changing the tape running speed without changing the drum rotation speed; and whereby the video tape is housed within a cassette that includes a non-contact type buffer memory for storing a list of contents of the video tape, the non-contact type buffer memory including a drive circuit for controlling said memory, being read when data is reproduced from the tape and being written when data is recorded to the tape.
7. A video tape reproducing device as defined in claim 6 , wherein: said driving control means controls the running speed of a video tape by said driving means; and said driving control means controls said driving means such that when the data quantity stored in said buffer memory is larger than a predetermined value, the running speed of said video tape is decreased; and when the data quantity stored in said buffer memory is smaller than the predetermined value, the running speed of said video tape is increased.
8. A video tape reproducing device as defined in claim 6 , comprising: memory readout means for reading the recorded contents of the memory means attached to said video tape to memorize the information to control the contents recorded on said video tape.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
November 22, 2000
August 15, 2006
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.